: I'm putting 93 octane in my 2000 Northstar. Am I wasting my money?



BeelzeBob
05-28-05, 09:27 PM
Are there any good reasons to use high-test for my 2000 DeVille DTS? If there's a decrease in performance when using 87, how noticable is it? I know 93 will probably give me a little more mileage, but is it worth it?

Night Wolf
05-29-05, 12:47 AM
Are there any good reasons to use high-test for my 2000 DeVille DTS?

Its a $55k high end luxury car = reason :)

really, how I think of it... owning a Cadillac.... an extra 20 cents/gallon shouldn't make a difference :)

But... I have heard that ALL NorthStars like premium and run best, but on 2000+ it can *safely* be used... don't know for sure though....

If I had any NorthStar it would get premium... the 4.9 requires it... the Oldsmobile gets regular, bet hey... its a 3800 V6 :) the 425 gets regular too... because it actually runs good on it... and if I used premium (as I have in the past) I would have to take a loan out every time I fill it up :)

carguy16
05-29-05, 10:19 PM
sal, your wasting your money. I tried the 93 octane route, I dont think it did anything, I didnt notice any performance or different starts. The car was made for 87, so give it 87, even if mileage goes up you still pay more for the gas, so you lose either way. I read in the newspaper in automotive, put in what your car calls for, I will never buy 93 unless it says i have too.
Are there any good reasons to use high-test for my 2000 DeVille DTS? If there's a decrease in performance when using 87, how noticable is it? I know 93 will probably give me a little more mileage, but is it worth it?

Jesda
05-29-05, 11:50 PM
The lower compression version of the Northstar will see no performance gain with 91+ octane. Midgrade or premium on occasion (once a month?) may be suggested for its more aggressive detergents.

BeelzeBob
05-30-05, 12:02 AM
Thanks, all. I know it's probably better, technically, to use the higher octane - but I really don't have money to waste. If it's not going to hurt my car, and I wont lose much regarding performance, I may start using 87..

slk230mb
05-30-05, 04:46 PM
Thanks, all. I know it's probably better, technically, to use the higher octane - but I really don't have money to waste. If it's not going to hurt my car, and I wont lose much regarding performance, I may start using 87..

Do it, I ran 87 in my 2000 Deville all the time and the few tanks of 93 I put in I saw the mileage decrease.

TomDeville
06-01-05, 01:52 AM
Hi Esteemed Community:

I have only ever used 91, 93 and 94
octane in the 2000 Deville 4.6 Northstar.
What can I reasonably expect if I move
'down' to 87, apart from a smaller credit
card bill? :hmm:

TomDeville :coolgleam
:coolgleam

Ralph
06-01-05, 01:56 AM
Your 2000 most likely has a knock sensor. I would just run regular unless performance really suffers, etc.

Me, I have to run premium and it's around 96 cents per litre! It keeps me from driving it too much. :shhh: I don't want engine detonation or spark plug damage.

nukeduster
06-02-05, 07:14 PM
Its a myth that using higher octane fuels gives you:

1.More horsepower
2.Better gas mileage
3.higher octane burns cleaner

1. Motors make power. The power isn't increase or decreased by using different grades of fuel. It is increased and decreased by advancing and retarding timing, and if the engine isnt pinging/detonating, the factory computer isnt going to retard your timing. It'll make the same power on 87 or 96 octane fuel AS LONG AS THE ENGINE MANAGEMENT CANT SENSE WHAT OCTANE IS BEING USED. Which, no motor can directly. You can program around a certain minimum octane, which is why aftermarket chip burners are able to extract more hp out of stock motors. They make the computer by default advance spark/timing by X degrees because it assumes you will only use 91/93 octane fuel.

2.The ECU will tell the injectors to pulse a certain ammount regardless of what grade fuel you use. If the pulse width is the same, and the fuel density is the same, then gas mileage should be the same.

3.Higher octane fuels USUALLY have more detergents in them, which make them burn cleaner. Higher octane however, in and of itself, is slower burning the higher octane you go, and as a result is actually WORSE. But this is usually offset by the fact that, again, USUALLY.. most gas brands put more detergents (Techron, etc) in their "high test" fuels to clean up excess carbon.

malcolm
06-02-05, 07:26 PM
Assuming the engineers over at GM know what you know, why are they recommending premium for the 05 Northstar? I previously owned a 99 Eldo and a 02 Seville with a Northstar and the recommendation was regular and I never had a problem. When I got the 05, out of habit I started filling up with regular and then found out after several tanks that premium was called for. I switched to premium. It's difficult to calculate the cost increase since gas has gone up so much in the last few months but I went from averaging about 100 a month to about 150 a month for fuel. I would rather spend that extra 50 on greens fees or beer but don't want to damage the engine either. What's the right thing to do?

TomDeville
06-04-05, 01:13 AM
Just to clarify; is the 4.6 2000 N.Star*
made for both 87 octane and
conventional oil?

:coolgleam

Night Wolf
06-04-05, 02:42 PM
the funny thing is though....

lets say your engines needs 93 octane, but there is a knock sensor

So the engine is pinging, but the knock sensor retards the timing... no ping...

so you are still running 87, and think its fine because "it isn't pinging" when in really it "is" but the problem is "fixed" so you'll never hear it...

that is the thing, with newer engines, it'll have to be very bad before you hear an engine ping.... so simply saying I don't hear it ping, I'll keep using it dosn't work...

but come on... 20 cents/gallon difference between regular and premium...

so say you fill up with 15 gallons once a week, that is $3/week... or $12/month

$12/month? you drive a Cadillac.... treat it like one, most people that own a Cadillac, or any other luxury car are pretty well off, or atleast in relation to similar people their age/area that are driving Civics and Accords... I really don't see what the fuss is all about.... I mean the difference is so small.....

nukeduster
06-04-05, 06:08 PM
We only use 87 octane in every vehicle sold except for supercharged vehicles through our dealer. Every dealer I know of does the same. If they tell you otherwise, they are probaby lying.

Unless your motor has 10+:1 c/r, you honestly shouldn't need anything but 87. Alot of automotive manufacturers list using premium because it has more cleaning agents in it, and its better safer then sorry.. alot of 87 octane fuels at some fueling stations are absolute crap quality. As are alot of 91 octanes. Theres no official regulation as to what you can ad to gasoline and still market it as such, as long as the R+M/2 = X advertised octane.

I only run 87 octane in my n/a motors. Turboed/SC'd motors, well, that depends on their tuning. Anywhere from 91-110(AV110 jet fuel) octane goes.

Night Wolf
06-04-05, 10:28 PM
Anywhere from 91-110(AV110 jet fuel) octane goes.

110 is NOT jet fuel... well, 110 isn't used much anymore, it is 110LL..... it is blue and is infact gasoline..... jet fuel is clear and is not gasoline... the 2 are totally different fuels.... you can run 110LL in your car, you'll just mess the cat up (no cat? then you are good :) ) if you run jet fuel in your car..... bye bye engine...

nukeduster
06-05-05, 05:37 PM
you can get unleaded 110 fuels, which is the main concern for your cat. anyhow, end of story, its a waste of money in alot of motors to run 91 octane. if even seen for the same motor, year to year, the user manual stating different octane # requirements for certain vehicles. (first year 91, second year 87)

anyhow, do as you wish.

cadibrougham
06-10-05, 08:02 PM
Use premium dont be cheap. who cares if its 50 cents more.

one thing to remember that has not been mentioned yet is OPEN LOOP mode(FULL RICH) and CLOSED LOOP mode on obd 2 vehicles. Also the most important is 02 sensors.

octane is anti knock. the cleaner your car burns, remember comb. temp. 1400 degrees. the cleaner the exhaust.

then your o2 sensors tell the ecm that theirs more o2 in the exhaust and thats what regulates fuel trim ign. timing etc etc etc
dont forget closed loop mode. thats what its all about. the exhaust determines what the ecm will do with the fuel.
so to tune up you obd 2 car what do you do? what do you tune? nothing you replace the 02 sensors they do all the tuning for you.

no you are not wasting your money it only is about 5 dollars more a tank and if you drive a cady then dont be upset by 5 dollars ok. and no im not rich.

TomDeville
06-14-05, 11:56 PM
Are there any good reasons to use high-test for my 2000 DeVille DTS? If there's a decrease in performance when using 87, how noticable is it? I know 93 will probably give me a little more mileage, but is it worth it?


Sir Sal;

The Esteemed Panel
appears divided on this
issue, which is likely a direct
consequence of the varied, valid
;and, meritorious opinions all around.

It might be like the conventional
oil versus synthetic thing, someone
being right may not necessarily make
one with another perspective wrong.

Accordingly, I remain confused. :hmm: :hmm:


Best Regards,


TomDeville :coolgleam :coolgleam
:coolgleam :coolgleam

GreenMachine
06-25-05, 12:08 AM
Heres some info that may help you all out:

Found at: http://www.100megsfree4.com/dictionary/car-dico.htm#OctaneNumber

octane number: Every brand of gasoline (http://www.100megsfree4.com/dictionary/car-dicg.htm#Gasoline) has an octane rating or number which indicates its ability to resist knocking (http://www.100megsfree4.com/dictionary/car-dick.htm#Knocking). When the numbers were first developed, the researchers found that normal heptane (a hydrocarbon (http://www.100megsfree4.com/dictionary/car-dich.htm#Hydrocarbon)) had almost no ability to resist knocking (http://www.100megsfree4.com/dictionary/car-dick.htm#Knocking) so they gave it an octane number of zero. Then they found that isooctane (also a hydrocarbon (http://www.100megsfree4.com/dictionary/car-dich.htm#Hydrocarbon)) was very resistant to knocking so they gave it the octane number of 100. To measure a particular sample of gasoline (http://www.100megsfree4.com/dictionary/car-dicg.htm#Gasoline) they discovered when it began to create detonation (http://www.100megsfree4.com/dictionary/car-dicd.htm#Detonation). Then they mixed isooctane to heptane to find out what percentage of isooctane created the same results as the sample of gasoline. In United States, there are two methods for determining the octane number depending upon operating conditions. The Research Octane Number (RON) is obtained when conditions are somewhat mild. The Motor Octane Number (MON) is obtained when conditions are somewhat severe and give a much lower number than the RON. The numbers on the gasoline pumps are usually an average of the RON and MON. Usually the pump number is about four numbers less than the RON. Thus if the automobile manufacturer recommends using gasoline with a RON of 91 or more, it would be acceptable to use pump gas rating of 87. The pump number is the anti-knock index (http://www.100megsfree4.com/dictionary/car-dica.htm#Anti-knockIndex) which is half the sum of the RON and the MON.

ALSO See this: http://www.gmtechlink.com/images/issues/arcv_pdf/4_00_e.pdf

bcs296
07-07-05, 01:55 PM
So GM dropped the compression from 10.3 to 10.0 for the 2000+ engines, correct? Generally, doesn't more compression = bigger explosion = more power, or something to that effect? Has anyone ever dynoed a pre-2000 engine against a post-2000 engine? I guess I'm wondering if the move to 87 also meant a slight drop in power.

bcs296
07-23-05, 12:02 AM
Been over 2 weeks since that post... bump.

scourge
07-23-05, 12:16 AM
Its a myth that using higher octane fuels gives you:

1.More horsepower
2.Better gas mileage
3.higher octane burns cleaner

No, it is a fact not a myth. GTRs run on 100+ Octane in Japan with power simply not possible on pump gas in the US. Plus, the computers have to be retuned to less power because the octane isn't as high as in Japan.

For fun and to test this theory, run with regular gas for awhile and then fill up your tank with premium and 2 gallons of toluene* and see if there is a difference.

*I can never spell this word correctly without a dictionary. :shhh: